"Scanning" infrastructure for transportation projects in creating digital assets

By cuoituan.tuoitre.vn - 10/02/2024

TTCT - Each transportation project will have a digital file of a 3D model representing all dimensions, shapes, locations, etc., of exposed structures as well as parts that are obscured in reality.

Documentation one way, reality another

A construction unit working on the installation of a drainage system on Nguyen Duy Trinh Street (Thu Duc City) reported that the project had to be halted at least three times to address incidents due to unexpectedly encountering underground structures. According to the technical documents, there are water supply pipes under Nguyen Duy Trinh Street at specific locations. Based on this, the unit designed the drainage system to be constructed in a different location.

However, while excavating according to the plans, the excavator bucket struck a water supply pipe, causing flooding at the construction site and the risk of cutting off water supply to the surrounding areas. The project had to be halted to address the water pipe damage, with the construction unit bearing all costs and facing penalties for the delay in construction.

In 2020, a construction project on Nguyen Thi Dinh Street caused a water pipe to burst and an optical fiber cable to be severed, resulting in a temporary loss of water and Internet service in the area. The construction unit asserted that the main cause of the incident was the incorrect positioning of the underground water pipe and fiber optic cable compared to the documentation provided by the responsible authority.

In 2023, many construction units reported to the Ho Chi Minh City People's Council about the situation where infrastructure projects had "documentation one way, reality another," with the positions of underground infrastructure on the drawings being significantly different from the actual situation. These construction units then had to spend a lot of time re-exploring and surveying the existing works. And many incidents occurred during the construction process, such as fiber optic cable cuts, water pipe bursts, etc., significantly affecting the lives of the residents, increasing costs, and construction time.

In September 2022, the authorities discovered that the Nguyen Huu Canh overpass had a severed underground prestressed cable. Accordingly, four bundles of underground cables at the main span of the bridge were severed during the repair of Nguyen Huu Canh Street, nearly 18 months before the discovery.

The construction unit responsible for road repair (a consortium between the 319 Corporation of the Ministry of Defense and Dong Son Infrastructure Investment JSC) was unaware of this incident until notified by the authorities. More surprisingly, the Project Management Board for Construction Investment of Transportation Projects later revealed that this unit did not have the completion records for the Nguyen Huu Canh overpass project. Therefore, the construction unit was unaware of the exact location of the underground prestressed cables, leading to their severance during repairs and the long delay before the incident was discovered.

Following the incident with the Nguyen Huu Canh bridge, the Ho Chi Minh City Department of Transport also discovered that many bridges managed by the department lacked numerous records, documents, and technical drawings. This means that another incident similar to the Nguyen Huu Canh bridge could occur at any time. According to the department, these structures were built many years ago, and the documents were lost during the storage and transfer process.

Mr. Luong Minh Phuc, the director of the Ho Chi Minh City Traffic Construction Investment Project Management Board, stated that many underground infrastructure projects also lack records, similar to the Nguyen Huu Canh bridge and road case. Therefore, construction units working on projects related to these structures are like "blind men feeling an elephant," not knowing what underground constructions exist or their locations.

There are multiple reasons for the lack of records, such as the construction projects being old, documents getting lost during transfers between various managing agencies, or construction units from different sectors not handing over completion records to the transportation sector. Additionally, there are instances where a project was completed but not handed over before another construction unit started a subsequent project...

However, there are many underground constructions that do have completion records and drawings, but subsequent construction units still frequently encounter problems. According to traffic experts, the reason is that the completion records are not accurate, and the supervising unit and the entity accepting the project previously failed to detect this. The most common situation is that during construction, if an incident occurs, the construction unit adjusts the position of the underground equipment but still completes the project according to the original design drawings. Another scenario is that the contractor constructs in the wrong location or deviates from the design but still reports it as correct.

"Ultrasound" the road to redraw the underground system

To address this situation, the Ho Chi Minh City Department of Transportation and related units are developing a data system for both old and new transportation projects in the city using BIM - GIS technology. Accordingly, transportation projects are scanned with 3D laser technology to survey their current state.

This technology will record all components and project items as they are in reality, and at the same time, redraw the diagrams and positions of these components and items according to the current state. Particularly, components and items that are obscured, as well as underground structures beneath the surface, will also be clearly depicted in 3D images.

The data mentioned will be compiled into a Building Information Model (abbreviated as BIM), which is then integrated with a Geographic Information System (GIS) to aid in urban planning and management tasks. More importantly, the information about the projects can be updated over time to reflect changes. For now, BIM - GIS technology is being utilized to collect data at new projects such as the metro system, Ho Chi Minh City's Ring Road 3, An Phu interchange, and more.

In addition to digitizing the records of new projects, BIM - GIS technology is also used to restore the technical documents of old infrastructure projects. This technology will survey and "ultrasound" to redraw the designs and diagrams of existing constructions, including the configurations of underground installations.

Mr. Luong Minh Phuc explained that digitizing construction information as described helps to establish the life cycle of a project. From 3D images, transportation projects can be evaluated for their current condition, quality, defects, damages that have appeared or are potential... Based on this, managing agencies can plan maintenance, preservation, and timely repairs for these transportation projects.

Digital records are very important in the process of maintaining, repairing, or constructing other projects related to transportation infrastructure. With digital records, construction incidents like the Nguyen Huu Canh overpass case or accidentally breaking water pipes and cutting fiber optic cables during roadworks can be avoided. Consequently, construction units can shorten construction time and save costs for both contractors and regulatory agencies.

Additionally, managing agencies can monitor the current condition and operational capacity of the infrastructure to calculate maintenance and repair schedules. When records are needed for comparison, operation, or maintenance, there will already be a complete dataset available, eliminating concerns about omissions or discrepancies," Mr. Phuc stated. ■